The use of portable, rechargeable electrochemical cells has been rapidly increasing in recent years. With developments in rechargeable battery technology, rechargeable batteries are used for power not only in traditional areas such as flashlights and small electronic devices but also in heavy duty power tools, temporary power sources, and even vehicles. Of course, rechargeable batteries are also widely used in the starting systems of internal combustion vehicles and tools. Many of the rechargeable batteries in use today are nickel-cadmium, nickel-metal hydride or lithium batteries. Recent advances in lead-acid batteries, such as those disclosed in U.S. Pat. No. 5,047,300 to Juergens and assigned to the assignee of the present invention, have increased the utility and the popularity of portable, rechargeable lead-acid battery systems.
Of course, some case or housing must be used to contain the cells that comprise a battery so that the cells' electrical energy may be safely and conveniently used and transported. Since many uses require the battery to be frequently recharged, the battery should be easily manipulable between a battery-powered device and a recharger. It is also desirable that a battery be compatible, perhaps with adaptations, with a variety of the connectors that are often found on battery-powered devices, so that the same battery may potentially be used with many different devices. A case that contains several cells is often termed a "battery pack" or a "power pack." In the present application, it should be understood that what is referred to as a "battery case" may contain several electrochemical cells, wherein each cell may comprise a plurality of electrodes or, for example, two long spirally-wound electrodes.
Many rechargeable battery cases and rechargers and tools useful therewith have been developed, and these devices address a variety of uses. U.S. Pat. Nos. 5,144,217 and 5,391,972 to Gardner et al. disclose a combination battery back/recharger wherein the charger may accommodate several battery configurations. U.S. Pat. No. 5,200,280 to Karasa discloses a device that surrounds a battery to prevent accidental discharge. U.S. Pat. No. 4,339,201 discloses a battery case to prevent terminal short-circuiting. U.S. Pat. Nos. 4,871,629 to Bunyea; 3,883,789 to Achenbach et al.; 3,999,110 to Ramstrom et al.; 5,368,954 to Bruns; 5,213,913 to Anthony et al., 5,208,525 to Lopic et al.; 4,084,123 to Lineback et al.; 5,089,738 to Bergquist et al.; 5,336,953 to Alleman; 4,616,169 to Proffitt; 4,447,749 to Reeb, Jr. et al.; 4,339,201 to Nagahara; and 3,757,194 to Weber et al. disclose latching arrangements and other mechanical and electrical connections between battery cases and electric devices.
U.S. Pat. No. 4,751,452 to Kilmer et al. discloses a battery case that precludes the battery from attempted recharge when the battery is of a non-rechargeable type. U.S. Pat. No. 5,296,314 to Millauer provides a battery case keyed to provide the appropriate voltage to selected electric devices.
None of these prior art devices, however, address the difficulties associated with lead-acid cells, such as filling, venting, and attaching end connectors. Some of these devices are meant to function in several electric tools; however, none of these devices are designed to allow the same unit of cells to be adapted to a variety of tools by substituting external connectors.